contains an old (and kind of hokey: I'm old enough to remember films with background music like this, but probably not many here are) video program describing the Nevada Fish and Game Department's successful effort to introduce the Himalayan Snowcock (Tetraogallus himalayensis) into the Ruby Mountains back in the 1950s and 60s.

Now, I would argue that this successful introduction of an exotic species supports the point of view that some introduced species can enhance the human experience in those areas into which they are introduced: think also of the cases of the brown trout, the common pheasant, the Hungarian Partridge. This is not to argue that the more numerous instances of destructive introductions (Common Starlings, the Cane Toad, Zebra Mussel, etc.) are any less catastrophic--nor is it a dimension of the argument for introducing species which are endangered in their indigenous ranges in order to conserve them. It is, however, an assertion that sometimes the introduction of an exotic species can be a good thing for the people in its area of introduction. This argument gains more prominence because of the growing attention being given to biological controls of nuisance species (themselves often introduced). I live in Virginia, and our area is beset with Brown Marmorated Stink Bugs. USDA is testing certain species of exotic parasitoid wasp which control the BMSBs in their native Asian environments. These little wasps would be heartily welcomed by those of us with a BMSB problem, and we also enjoy seeing the occasional pheasant. So, what do you folks think about the issue?

Good point - and not all current residents of an ecosystem can be interpreted to have been here forever.

I'll add that zebra mussel is not necssarily a problem. In the Great Lakes, it's been credited with reduction of particulate pollution and subsequent increase in fish populations. On the otherside they've reduced populations of "native" mussels and been the source of avian botulism. That it blocks cooling vents for power plants is not an environmental problem per se. You can even see fishing shows targeting the hated snakeheads.

Exotic species should never be introduced. Period! The examples that each of you gave as being benign are not benign. Brown trout outcompete native trouts and eat native species. They are a huge problem in places like the Grand Canyon, where they devour the endangered native fishes. Pheasants outcompete native grouse, such as sage grouse and prairie chickens, which are now threatened species. I see no reason why hunters couldn't hunt them instead of pheasants. Chukars and Hungarian partridge compete with California and Gambel's quail. While zebra and quagga mussels do clean up water, I questions JorgeLobo's contention that they've "been credited with...subsequent increase in fish populations." Juvenile fishes need the phyto- and zooplankton that the mussels consume. If I am not mistaken, I believe that these mussles have been "credited" with reducing the walleye populations in the Great Lakes.

While exotic introductions may benefit the narrow interests of some humans, the vast majority of them are detrimental to the ecosystems into which they are unleashed. The risk is far too great!

"Nothing in biology makes sense except in the light of evolution."Theodosius Dobzhansky"Most people who hate the idea of evolution do so because if it was working properly, they'd be dead."Anonymous

I think we should put a sensible ruling on the introduction of non native species. I.E. IF it's big enough to shoot, and has never reached pest proportions in its place of origin it's OK. I would certainly be against the introduction of a parasitic wasp. It might decide to prey on loads of rare and beneficial insects in its new habitat, and once thriving would be impossible to eradicate, worse even than the cane toad.I would however love to see some of our iconic rare species like pandas lemurs gorillas or orangutans placed in the wild, in similar latitudes across the globe, and allowed to thrive. It would surely be worth putting in some plantations of their native food plants to get them going wouldn't it? They would probably soon learn to switch to the food plants of their new environmentAfter all in our modern world where so much organic material is moving backwards and forwards between continents, containment of pest species isn't really an option anyway.